CA1300192C

CA1300192C - Steering knuckle assembly

Info

Publication number: CA1300192C
Application number: CA000545358A
Authority: CA
Inventors: William L. Kozyra; Andrew B. Macisaac
Original assignee: Budd Co
Current assignee: ThyssenKrupp Budd Co
Priority date: 1986-09-24
Filing date: 1987-08-26
Publication date: 1992-05-05
Anticipated expiration: 2009-05-05
Also published as: JPS6387377A; EP0261444A2; EP0261444B1; BR8704864A; MX160062A; EP0261444A3; ATE95128T1; KR910003763B1; KR880003763A; US4722540A; DE3787606T2; DE3787606D1

Abstract

ABSTRACT OF THE DISCLOSURE
An improved steering knuckle assembly of the type including a stamped knuckle housing portion. In accordance with this invention, the conventional means for attaching suspension components to the knuckle which includes a tapered stud and correspondingly tapered bore within the knuckle are eliminated. Instead, the knuckle housing features a bore which is surrounded by a hemispherical seat region. The protruding stud of the ball joint or steering link extends through the bore and includes features which conform to the shape of both sides of the hemispherical seat to clampingly engage the suspension component to the steering knuckle housing. Another feature according to this invention is a steering knuckle configuration which eliminates the conventional protruding arm necessary for attachment to a steering link. A modified steering link is provided having a protruding stud which attaches directly to the concave-shaped steering knuckle housing.

Description

~L3~ 2 IMPRDVED SIEERING KNUCKLE AssEMsLy BACRG~oUND AND SUMMARY OF THE rNVENlICN
This invention relates to motor vehicle suspension components and particularly to a steering knuckle assembly adapted to support a steerable wheel.
Conventional motor vehicles have a steering knuckle which is typically constructed as a one-piece forged or cast unit. Such integral units may include a wheel bearing carrier, torque arms for supporting a disc type brake caliper, and points of attachment for suspension ~omponents. Although such steering knuckles perform satisfactorily, it is desirable ~o pr,~vide enhanc~d structural and cost optimization for these units. It is particularly desirable t~ r~duce the weight of the steermg knuckle ass3nbly since weight r~du~tions in this area provii-~e the two-fold ai~vantage of reducing total vehicle weight and suspension unsprung mass.
Overall vehicle weight reductions improve performa~,ce and fuel efficiency.
Reductions in unsprung mass are desired to enhance vehicle ri,e and h2ndling. It is further ,esirable to provi~e an improved steerLng knuckle assembly which can be produced at a lcwer cost than current designs.
Another desirable feature for a steering knuckle assembly is the ability to adapt it to different motor vehicle ap2lications.

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The objective of the present invention is to provide the above-mentioned desirable features for a vehicle steering knuckle. A
preferred embodiment of a steering knuckle assembly according to this invention is formed fram two mechanically attached components. A bearing carrier component may be fabricated by conventional casting or forging processes and includes the wheel bearing carrier and torque arms for supporting a disc brake caliper assembly. The remaining portion of the steering knuckle assembly is formed by a concave shell-shaped housing preferably manufactured using metal stamping processes. mis composite structure provides a significant weight advantage and cost advantage as compared with conventional designs primarily due to the use of stamped components. The steering knuckle assembly according to this invention may be adapted to different motor vehicle applications by changing the configuration of the stamped housing, enabling the same cast or forged bearing carrier component to be used for various applications. When assembled, the steering knuckle assembly acoording to a preferred embodiment of this invention mechanically traps the wheel beæ ing within the steering knuckle assembly.
The steering knuckle assembly according to this invention further enables the stamped knuckle housing component to have a simplified configuration which eliminates the protruding steering arm of oonventional steering knuckle designs. Instead, a navel steering link is employed which is fastened directly to a side wall portion of the knuckle housing.
In acoordanoe wqth another feature of the steering knuckle assembly according to this invention, a novel means for fixing the ball joints of the vehicle suspension system to the steering knuckle is disclo~ed. The attachment system according to this invention eliminates ~3~0~9~:

the necessity of providing bushings having internally tapered bores as attachment sockets. The attachment system employs a hemispherically shaped seat formed by the knuckle housing which mates with oomplementary shaped surfaces of the ball joint attaching stud.
Additional benefits and advantages of th~e present mvention will beccme apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embocinents and the appended claims, t~ken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a steering knuckle asse~bly in accordance with this invention shown fro~ an inboard viewing position and shcwn with associated components including a cartridge-type wheel bearing, a disc brake rotor, and a drive hub;
Figure 2 is an exploded perspective view of the steering knuckle assembly according to this invention showing the components thereof in unassembled positions and further showing associated ccmponents including a hub, a disc brake rotort a brake caliper, and a steering link;
Fig~re 3 is a cross-sectional view ta~en along line 3-3 of Figure 1 showing the various components of the steering knuckle assembly with associated suspension component;
Figure 4 is an exploded pictorial view of the hemispherical suspension attachment syste~ according t~ this invention; and Figure 5 is a cross-sectional view taken along line 5-5 of Figure 1.

DEIAIIED DESCRIPrION OF T~E IN~ION
A stee~ing knuckle assembly in accordance with this invention is shown in the drawings and is generally designated by reference character 10. The primary components of steering knuckle assembly 10 are knuckle housing 12 and bearing carrier 14. Steering knuckle assembly 10 is designed to support disc brake rotor 16 and hub 20 for rotation and provide a mount for disc brake caliper assembly 18, which is comprised of caliper 22 and shoes 24. Steering knuckle assembly 10 further provides mounting points for various suspension components, such as ball joints 38 and 40, and steering link 42. Alternately, knuckle assembly 10 could be configured ! to accept other types of suspension components such as strut type i suspension units, etc. Steering knuckle assembly 10 described and illustrated herein is intended for use with a driven axle. The novel features of this invention, however, are also applicable to non-driven wheel configurations.
Bearing carrier 14 is preferably made by a casting or forging process and includes an axially elongated internal bore 26 which is dImensioned to accept cartridge wheel bearing assembly 28. Preferably, the diameter dimensions are chosen to provide slight interference between bore 26 and wheel bearing assembly 28, thereby providing "press fit"
installation of the bearing which is desirable to avoid rattling and provides accurate bearing alignment. Bore 26 termina~es at its outboard end in a radially inward ridge which forms shoulder 30. The diameter of shoulder 30 is significantly less than the outer diameter of bearing assembly 28, so that the shoulder acts as an abutment to a~ially retain the wheel bearing from being withdrawn from bearing carrier 14. Bearing ~3~19~

carrier 14 further includes an integrally formed pair of radially extending and angularly offset torque arms 32 and 34 which support disc brake caliper 22 and disc brake shoes 24. Tbrque arms 32 and 34 provide reaction points enabling caliper assembly 18 to exert a frictional retarding foroe on disc brake rotor 16. Bearing carrier 14 further forms a radially extending flange 36 having a number of ~hreaded bores 44 therethrough which are radially spaced to encircle bore 26.
Steering knuckle housing 12 is preferably formed from sheet metal stock. Housing 12 could be formed by a progressive die metal stamping process wherein parts are moved from one work station to the next as they are formed from metal blanks to finished parts. Since hcusing 12 requlres a considerable degree of deformation of the metal, mild steel is a preferred material. Housing 12 is fonmed in the shape of a concave shell and includes a generally flat center surface 46, ~nd a peripheral edge flange portion 48 extending generally transverse from the center surface.
Within center surface 46 is central ap~rture 50 which preferably has a diameter or a cross-sectional dimension smaller ~han the outer diameter of cartridge wheel bearing as~enbly 28. This configuration provides another abutment for mechanically trapping cartridge wheel bearing assembly 28 within bParing carrier 14. Radially spaoed around aperture 50 are a number of fastener bores 52 which are positioned in registry ~ith threaded bores 44. Threaded fasteners 54 pass through fastener bores 52 and threadingly engage threaded bores 44 to clamp steering knuckle housing 12 against bearing carrier 14.
It is necess y during assembly of knuckle housing 12 to bearin~
carrier 14 to insure the desired relative angular relationship between these comFonents. Therefore, it is desirable to provide means for i ~13(~ 2 preventing asse~bly unless the components are properly oriénted. This feature is accomplished for the embodiment shown in the drawings by unevenly radially spacing bores 44 and 52, so that they are aligned only when the desired relationship exists. Other possible approaches include keying the parts together such that the parts interengage only in the desired assembled part position.
In accordance with this invention, novel means are proviaed for affixing suspension compo~ents to knuckle housing 12. In accordance with prior art techniques for affixing ball joints to the steering knuckle, tapered bores are provided within the knuckle housing or bushings having tapered bores therein are attached to ~he housLng. A protruding stud from the ball joint and steering link has a correspondingly shaped tapered shaft portion. me ball joint stud has a threaded end which allcws a threaded fastener to attach the knuckle to the ball joint. In accordance with this invention, however, such tapered bore ~d shaft oomponents are eliminated.
Instead, ball joints 38 and 40 each ~eature extending threaded stud portions 102. At the point of attachment of ball joints 38 and 40 to knuckle housing 12, bores 106 and 108 are formed through t~e knuckle housing peripheral edge flange portion 48. In the area of housing 12 surrounding bores 106 and 108, the housing forms hemispherical seats 110 and 112 which define a concave surface on one side of the knuckle housing and a convex surface on the opposite surface. Ball joints 38 and 40 each include washer 114 which is fixedly mounted to stud portion 102 and forms a convex hemispherical surface which conforms with hemispherical seats 110 and 112. Washer 116 is provided and is adapte~ to be loaded onto stud portion 102 and defines hemispherical surfaces w~lementary with that of seats 110 and 112. Fastenlng nut 118 additionally includes a seat surface ~3~9;~

120 having a concave surfaoe which conforms to the convex surfaoe of washer 116. Onoe fastening nut 118 is securely fastened, knuckle housing 12 is firmly clamçed between washers 114 and 116 which are fastened to ball joints 38 and 40. me provision of the hemispherical seats penmits mounting studs 102 and 104 to establish the desired relative orientation with respect to the steering knuckle 12 and remain in that position after fastening of nut 118. In addition, the provision of the various reinforcing memkers including washers 114 and 116 reinforces the area of knuckle housing 12 in the region of attachment of ball joints 38 and 40.
In accordance with another principal feature of this invention, a modified system for attaching steering link 42 to knuckle housing 12 is provided. Conventionally, a steering knuckle defines an extending arm to which the steering link is attached. The conventional steering link has a protruding threaded stud having a tapered surface which extends either upwardly or ~bwnw~rd1y in a vertical direction into a bore in the steering link anm having a tapered inside surface. In accordance with this invention, the s~eering link stud 122 is inserted directly into peripheral edge flange por*ion 48 of knuckle housing 12 through bore 126. Various attaching means may be employed for affixing steering link 42 to knuckle h~using 12, including the previously mentioned hemispherical seat arrangement. As shcwn in Figure 5, tapered bushing 124 is positioned between bores 126 and 128 in housing 12 and reinforoenent plate 130, respectively.
Wheel bearing assembly 28, which is supForted by steering knuckle assembly l0, is a cartridge-type bearing assembly. mese types of bearing assemblies are integral units which hav~ permanently assemblecl inner and outer raoes. Wheel bearing assembly 28 is sealed from ~3~ 92 the environment by inner and outer bearing seals 68 and 70. Preferably, seals 68 and 70 are identical, thereby enabling reversible installation of bearing 28. An additional seal 96 is preferably provided which is press fit into knuckle housing aperture 50. Seal 96 includes sealing lips which make sliding contact with drive shaft 72 thereby further acting to prevent contamunation of wheel bearing assembly 28. Seals 68 and 70 preferably sealingly contact seal 96 and hub 20 respectively. Drive shaft 72 typically would include one or tw~ constant velocity type universal joints 74. Universal joints 74 permit a degree of relative angular misalignment between portions of drive shaft 72, enabling suspension travel without damaging the drive shaft. Drive shaft 72 further includes an extending splined shaft 78 having a threaded end 80. Hub 20 forms an internal splined surface which corresponds and mates with the splines of shaft 78 and has a radially extending flange 82 which provides a mounting location for a plurality of wheel m~unting studs 84. ~ub 20 has a cylindrical surface or nose 86 which preferably frictionally engages the inner race of cartridge wheel bearing assembly 28 when these parts are assembled.
Disc bra~e rotor 16 may be a conventional integral unit or a composite type having a stam~ed shPet m~etal oenter 88 with an outer cast rotor surfaoe 90. me oo~posite coniguration of rotor 16 provides a ~Dre mass efficient unit. Center 88 includes a plurality of radially spaced ~ores 92 which receive wheel mounting studs 84.
m e assembly and operati~n of steering knuckle assembly lO will now be described in detail. The assembly of the various components is best explained with particular reference to the exploded pictorial view of Figure 2. During initial assembly, cartridge bearing assembly 28 is press fit within bore 26 of bearing carrier 14. Due to the pres~nce of shoulder -` ~30~9~ -30, it is ne oessary to load and press cartridge wheel bearing assembly 28 from the inboard side of bearing carrier 14. Bearing assembly 28 is depressed within bore 26 until it engages shoulder 30 which prevents further displacement.
Steering knuckle housing 12 is loaded into position such that fastening bores 52 are aligned with threaded bores 44. mereafter, threaded fasteners 54 are installed, thereby fi~ing these t~o oomponents.
Sin oe oe ntral aperture 50 has a radial dim~ension smaller than the diameter of the outer raoe of cartridge wheel bearing 28, the bearing b~ecomes 1 trap~ed between abutments formed by steering knuckle housing 12 and shoulder 30 of bearing carrier 14. Bearing 28 is therefore retained within I steering knuckle assembly 10 both k~ press fit and mechanical trapping j engagement. This fastening approach provides more secure engagement of ¦ wheel bearing assembly 28 than according to prior art designs wherein a press fit is t~e only mechanism used to secure the wheel bearing. Seal 96 is press fit into aperture 50 of housing 12~ Hub 20 is preferably press fit into the inner race of cartridge bearing assembly 28. Drive shaft 72 is ins~alled s~ch that splined porton 78 passes through and engages within a correspondingly splined internal bore of hub 20. Finally, rotor 16, caliper 22 and brake shLes 24 are installed.
While the above description constitutes the preferr d enbodlments of the present invention, it will be appreciated that the invention is sus oeptible to nodification, variation and change without departing frcm the proper soope and fair meaning of the accompanying claims.

Claims

1. An improved suspension component mounting system adapted for attaching a vehicle steering knuckle assembly to a ball joint or a steering link of the type having a protruding attachment stud coupled to a flexible coupling comprising:
said steering knuckle assembly having a housing defining a peripheral edge flange portion, a bore defined within said peripheral edge flange portion, a seat surrounding said bore defining a concave housing surface on one surface of said edge flange portion and a convex housing surface on the opposite surface of said edge flange portion, and said attachment stud having:
a threaded stud portion, a convex stud surface engageable with said concave housing surface, a concave stud surface engageable with said convex housing surface, and fastener means for clamping said concave stud surface and said convex stud surface against said concave housing surface and said convex housing surface, thereby rigidly fastening said attachment stud to said steering knuckle assembly.

2. The improved suspension component mounting system according to claim 1 wherein said concave and convex housing surfaces and said concave and convex stud surfaces are generally hemispherical in shape.

3. The improved suspension component mounting system according to claim 1 wherein said convex stud surface is defined by a first washer member rigidly affixed to said attachment stud.

4. The improved suspension component mounting system according to claim 1 wherein said concave stud surface is defined by a second washer member slidably disposed on said threaded stud.

5. A steering knuckle for a vehicle adapted to rotate about a generally vertical axis in response to steering inputs from a steering link having an attachment stud projecting from a pivotal coupling, said knuckle supporting a ground engaging wheel rotatable about a generally horizontal axis comprising:
said steering knuckle having a peripheral flange having surfaces generally parallel to said horizontal axis, and coupling means for engaging said steering link defining an aperture within said peripheral flange having its longitudinal axis generally perpendicular to said generally vertical axis whereby said attachment stud is oriented along said aperture longitudinal axis and wherein said pivotal coupling is positioned adjacent said steering knuckle peripheral flange when said attachment stud is engaged by said coupling means.

6. The improved steering for a vehicle according to claim 5 wherein said steering knuckle is defined by a stamped metal shell having a generally planar central portion and edge portions defining said peripheral flange.

7. The improved steering knuckle for a vehicle according to claim 5 wherein said peripheral flange further defines mounting points for a pair of ball joint assemblies which define said generally vertical axis.

8. The improved steering knuckle for a vehicle according to claim 5 wherein said aperture is defined by a bushing affixed to said peripheral flange.

9. The improved steering knuckle for a vehicle according to claim 8 wherein said bushing defines an internally tapered bore.

10. A steering assembly for a vehicle adapted to rotate about a generally vertical axis in response to steering inputs from a steering link, said steering assembly supporting a ground engaging wheel comprising:
a steering knuckle having a peripheral flange having surfaces generally parallel to said longitudinal axis and having coupling means defining an aperture having its longitudinal axis generally mutually perpendicular to a portion of said peripheral flange surface and said generally vertical axis, a steering link having an elongated bar portion and an attachment stud with a pivotal coupling therebetween, said attachment stud being received by said coupling means such that the longitudinal axis of said stud is generally perpendicular to a portion of said peripheral flange surface, and a pair of ball joints coupled to said steering knuckle enabling said knuckle to rotate about said generally vertical axis in response to steering inputs from said steering link.